[PATCH v5 12/15] x86, module: Ignore __typeid__ relocations

Sami Tolvanen
2021-10-13T18:17:30Z

The R_X86_64_8 __typeid__* relocations are for constants the compiler
generates for indirect call type checking with CONFIG_CFI_CLANG. Ignore
them when loading modules.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
---
arch/x86/kernel/module.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 5e9a34b5bd74..c4aeba237eef 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -197,6 +197,10 @@ static int __apply_relocate_add(Elf64_Shdr *sechdrs,
val -= (u64)loc;
write(loc, &val, 8);
break;
+ case R_X86_64_8:
+ if (!strncmp(strtab + sym->st_name, "__typeid__", 10))
+ break;
+ fallthrough;
default:
pr_err("%s: Unknown rela relocation: %llu\n",
me->name, ELF64_R_TYPE(rel[i].r_info));
--
2.33.0.1079.g6e70778dc9-goog